The present invention represents an improvement upon the subjects matter of the above-referenced U.S. Pat. No. 7,536,883 issued May 26, 2009 to Tien-Kao Liu entitled VANDAL-RESISTANT COMBINATION PADLOCK.
In particular, the present invention relates to strong, attack resistant, corrosion resistant inserts of novel configuration for use within combination operated padlocks, and to the use of inserts of novel configuration for strengthening and providing attack resistant and corrosion resistant improvements in padlocks of the type having a shackle that is released by turning indicia carrying wheels or dials to set a combination that permits a lever-like blocking member (or “rocking claw” as it is sometimes called) to pivot within an open area of a padlock's housing carried frame (i.e., within a so-called “frame defined space”). The dials extend into the frame defined space and interact with at least one operating component of the padlock that pivots within the frame defined space. In preferred practice the insert has two substantially identical question-mark-shaped tines that extend toward and between different adjacent pairs of the dials.
The referenced Liu patent discloses a chunky, cast zinc metal insert intended to inhabit and to substantially fill otherwise unused territory within a “frame defined space” of a combination operated padlock. The Liu insert is configured to closely embrace portions of an operating component that moves in a pivotal manner within the frame defined space. In essence, the insert of Liu is intended to extend so near to major portions of the movable operating component as to closely sandwich these portions in efforts to protect selected operating components of the padlock from damage due to an application of external force, or due to manipulation of operating components by using small tools inserted alongside dials of the padlock to defeat and open the padlock.
The present invention provides a much differently configured insert from that disclosed in the patent of Liu. Inserts embodying the preferred practice of the present invention are formed as brass stampings that are openly configured and designed to extend near to, without serving to closely sandwich, portions of the operating component that is supported by, and is pivotally movable within, the frame of a combination operated padlock.
In preferred practice, inserts that embody features of the present invention are formed from corrosion resistant brass, as stampings, and are designed to be of uniform thickness having a configuration that fits cleverly around and among operating components of the padlock to prevent the operating components from being manipulated to effect an unauthorized unlocking of the padlock. The insert preferably also serves to strengthen the padlock, thereby enhancing its resistance to forceful attack.
More particularly, the invention relates to improvements in dial operated combination padlocks that have evolved from padlocks of the type disclosed in U.S. Pat. Nos. 2,853,868 and 3,419,893 issued to Carl A. Valstrom, U.S. Pat. No. 3,817,063 issued to Merton S. Williams and, more recently, the referenced Liu patent. The Valstromm, Williams and Liu patents identified above are referred to later herein as the “Combination Padlock Patents.” These and other patents disclose padlocks that utilize similarly configured frame supported sub-assemblies have shaft-supported dials which extend into so-called “frame defined spaces” wherein movable operating components known as “blocking members” pivot to selectively permit and prevent unlocking of U-shaped shackles of the padlocks in response to a turning of dials to set combinations that enable the blocking members to move in a way that causes the hardened steel shackles of the padlocks to unlock and open.
Although the aforementioned Williams patent discloses an improved padlock construction having a so-called “filler block” installed in a thin upper end region of a space defined by a frame of the padlock's control assembly, the Williams filler block is quite thin, is severely notched thereby weakening its strength at a central location, has a generally trapezoidal shape that extends into engagement with only small, spaced portions of the frame, and leaves open and unoccupied a sizable region or territory within the frame-defined space of the padlock—a space into which small tools and other foreign objects can be inserted if efforts are made to defeat the operation of the lock by manipulation, bending and/or breakage of components of the padlock—a space within which portions of the frame, dials, shaft, lever-like blocking member or other operating components can be deformed or displaced if subjected to external pressure or pounding in attempts to defeat the padlock by component breakage, deformation or displacement.
Although the presence of the thin, trapezoidal shaped filler block disclosed in the Williams patent does help to reinforce and rigidify an upper end region of the frame located a substantial distance from the dials and shaft that supports the dials, the remotely located filler block provides no direct support or reinforcement to the end region of the frame where the dials and the shaft are located, and does little to confine the lever-like blocking member or other components so they are permitted to move only within protected, permitted zones of movement.
Any benefit obtained by use of the Williams filler block can be lost if the filler block should crack, deform or break either as the result of its being severely centrally notched to accommodate blocking member movement, or due to its being provided with a sizable hole at the same central location as the notch—a hole into which a drive pin or threaded screw is forcibly driven at the conclusion of the padlock's assembly procedure to hold components of the padlock in assembled relationship.
Liu recognized that the small trapezoidal-shaped filler block of Williams could be improved upon, and that a significant amount of unoccupied territory within the frame defined space found in combination operated padlocks of the type disclosed in the Williams patent remains open and might be utilized disadvantageously during efforts to pry, pick, break or manipulate operating components of the padlock. Liu also recognized that the thin, trapezoidal-shaped filler block of Williams does nothing to directly support the dials or the shaft, or to confine movements of such components as the dials and the blocking member to restricted zones within which these components should be confined and permitted to move, or to prevent these components from being deformed or displaced to defeat operation of the padlock. Liu therefore provided a significantly larger filler block (which Liu referred to as a “claw mount”) shown in FIG. 1 hereof, which is copied from FIG. 6 of the Liu patent.